the dorbel daily

Friday 16 December 2011

Lastgamephobia II: The Sequel

Those of you who read the comments will have seen Timothy Chow's comment on the last post. I reproduce it here for those who didn't. Thanks Timothy, but I fundamentally disagree with you. Here's why.

"There is one reason you may not want to double at 4a2a as aggressively as the bot says you should. A lot of positions that the bot drops at this score will be easy money takes and therefore will be taken by many players. If your opponent is likely to take next turn even though it is technically a drop, then you can't actually lose your market."

This is worth looking at more closely. The examples that I gave are not early doubles in the sense that they are technically wrong, they are correct doubles and to wait a turn loses equity. If we wait until there has been a market losing sequence and yet our opponent incorrectly takes, we don't gain anything. It's the same game with the cube in the same place as it would have been when we doubled correctly earlier. In order to reach that point we have to make one or more cube errors and then rely on our opponent to make a mistake in order to avoid losing equity by losing our market!
Lastgamephobia afflicts both doublers and takers. If you open with a 3-1 and the opponent rolls a lemon, 6-3 say, then believe me you can and do get wrong passes by correctly doubling immediately. At this score, lastgamephobia sufferers also get sudden attacks of gammonphobia. You can't gain by missing a correct double at this score, only lose.

Traditional cube play technique was to try and double as close to the point where a take becomes a pass as possible. There are several drawbacks to this.
First, it requires very precise judgment to identify when you have reached this point and balance it against market losers. Doubling at the first correct point is a lot easier to spot, because you only need to be in the ballpark.
Second, you almost always have to miss several correct doubles to get to that point. Doubling early means that you might make a mistake when you double, but it will be the only one that you make in that game.
Thirdly, if you double at what was traditionally considered the optimum point, i.e. at the place where you gain a theoretical point by getting a take or an actual point when the opponent passes, it isn't then possible for the opponent to make a mistake! She loses a point either way. Doubling early allows her to make a big mistake by wrongly passing.

The bots, who play better than humans 24/7, double early. The very best players and there are a few who consider a PR in excess of 2 to be playing badly, double like the bots do. We have nothing to lose and everything to gain by trying to emulate them. In the process, we will certainly make matches shorter, but dont be afraid of that. It's a game of aggression. Make aggressive doubles and reap the rewards.
Enjoy the game!

8 comments:

Gallon Jug said...

It is interesting on Play 65 that a huge number of players sporting Turkish flags double instantly one start of almost any game.

And darn me if they do not win a lot of games even when seemingly offering very bad early doubles.

Gallon Jug said...

Having said that I won 3 straight today on GG by doubling more aggressively as per Professor Dorbel's discussion.

Timothy Chow said...

Paul, it's true that you don't gain anything if you technically lose your market and your opponent takes. However, my point is that you don't lose anything in those sequences by waiting a turn. The gain from waiting comes from the sequences that are favorable to your opponent and you wish you hadn't doubled.

Timothy Chow said...

By the way, regarding your comment that the very best players double like the bots do, this is a bit of an exaggeration. I don't know who you consider to be the very best players, but since you've spoken highly of Stick Rice before, he definitely adjusts his cube play according to his opponent. If he's playing a match against someone who has demonstrated that he's a deep taker, then Stick will sometimes deliberately hang on to the cube at a score like 4a2a even if he knows for sure that it's a borderline bot double. Also, on rec.games.backgammon, Stick recently said that he will often play on even if he knows the bot will think that's the position is not quite too good.

Having said all that, I of course agree with you that most intermediate players don't double enough and should be encouraged to double more aggressively.

dorbel said...

Thanks again Timothy. I think the missing phrase from everything I write should be "in the long run". I don't think that in the long run you gain anything from delaying a double, for the reasons that I give.
I am sure that all the best players, of which Stick is clearly one, vary their cube play according to their opponent. For the rest of us who don't play at that level and in my case never will, shipping it in early pays big dividends at all scores where aggressive and gammonish doubling is appropriate.
Thanks again for all your interest and input. I look forward to more of it in the future, particularly when critical!

ah_clem said...

IIRC, the conversation with Stick included a rant about how most players "cash like donkeys" instead of playing on for gammon.

Of course, with an early double you've precluded yourself from cashing like a donkey.

Timothy Chow said...

Paul, I'll say again that I believe your emphasis on aggressive doubling is right on target for the vast majority of players. Still, your latest comment about "in the long run" does make me want to emphasize that a decision not to double is always a decision for one roll only. If I hold on to the cube at 4-away/2-away because I feel confident that my opponent will take next turn no matter what happens, then I must revisit this decision on the very next roll. Or if I'm in a situation that I think is too good and I play on, again I must revisit this decision on the very next roll. A decision to refrain from doubling must never be thought of as a "long run" decision that you think about now and then don't need to think about again until some distant time in the future. Every roll is a cube decision!

With this concept firmly in mind, we can see that when deciding whether to hold the cube in a borderline 4-away/2-away situation (or any other situation for that matter), we should only consider what will happen on the very next exchange. If you can't lose and might gain on this very next exchange by not doubling, then you shouldn't double this turn. You should definitely not think, "If I don't double now or on the next turn or on the next turn after that or the next turn after that or..., then I risk losing out in the long run, so I should double now." Refraining from doubling this roll is not a commitment to refrain from doubling next turn as well.

dorbel said...

By "In the long run" I mean over the course of hundreds of matches. Of course if we decide not to double, we need to think again on the next and subsequent turns. One of the benefits of making a cube turn at the first reasonable opportunity is that we can't then make a mistake, or several mistakes subsequently. It also conserves brain power!